The effect of loss of visual input on muscle power in resistance trained and untrained young men and women.

Visual impairment has been shown to reduce muscle power when compared with that in sighted individuals. The purpose of this study was to assess whether the loss of visual input affects lower limb muscle power production in sighted men and women who are resistance trained and untrained. Twenty-seven college-aged participants (19-23 years) performed a seated double-leg press with and without visual input (resulting from being blindfold) in 2 separate counterbalanced trials. Lower limb concentric power was calculated by measuring the distance and time a leg press footplate was displaced while lifting 60% of 1-repetition maximum as quickly as possible. Loss of visual input reduced power output by 22.8 W (-6.4%) in all participants (p < 0.01). When resistance training status was taken into account, resistance trained participants (n = 12, trained >2× per week) did not lose power output (4.4 W, -1.1%, p = 0.90), whereas untrained men and women (n = 15) had significantly less power when visual input was removed via blindfold (37.6 W, -11.7%, p < 0.01). Untrained women experienced the greatest decrease in power when blindfolded (39 W, -15.9%, p < 0.01). Muscle power decreases in the absence of vision, but a regular strength training program attenuates this occurrence in young men and women. In practical application, strength training interventions may be successful in protecting individuals from losses in muscle power when visual input is removed.

Self-estimation of Body Fat is More Accurate in College-age Males Compared to Females.

The objective was to determine the effect of gender on the ability to accurately estimate one's own body fat percentage. Fifty-five college-age males and 99 college-age females participated. Participants estimated their own body fat percent before having their body composition measured using a BOD POD. Participants also completed a modified Social Physique Anxiety Scale (SPAS). Estimated body fat was significantly lower compared to measured body fat percent in females (26.8±5.6% vs. 30.2±7.0%, p<0.001) but not in males (16.8±6.8% vs. 18.1±8.3%, p=0.09). The mean difference between estimated and measured body fat was significantly higher for females compared to males (p<0.001). There was a moderate, significant correlation found between measured body fat percent and SPAS score for males (r=0.331, p=0.014) and females (r=.427, p<0.001). Males estimated their body fat percent more accurately than females. Despite these findings, 62% of males and 76% of females underestimated their body fat.

Survey of sickle cell trait screening in NCAA and NAIA institutions.

BACKGROUND: Screening for sickle cell trait (SCT) in athletes has been recommended by several professional organizations; however, it is not known how many colleges and universities have implemented such screening in athletes. AIMS: This study examines factors related to policies and procedures of SCT screening at colleges and universities, including all divisions of the National Collegiate Athletic Association (NCAA) and the National Association of Intercollegiate Athletics (NAIA) programs. METHODS: A total of 375 head athletic trainers or directors of sports medicine from NCAA and NAIA schools responded to an online survey. RESULTS: 21.8% of the respondent institutions screened all of their athletes for SCT, with Division I institutions having the highest rate of screening at 44.6%. A total of 30.1% of the respondent institutions indicated that they screened some of their athletes, with 66.9% of Division I institutions having the highest incidence. Over 26% of respondent institutions did not know if any of their athletes had SCT. Overall, 57% of the institutions counsel athletes about complications of SCT, and 40% of the institutions modify workouts for the athletes. Division I institutions had the highest incidences, with 87.7% providing counseling and 66.1% modifying workouts. The most common criteria for screening are race/ethnicity and family history of SCT. When asked to provide reasons for not screening all athletes, 71.6% of all respondent institutions indicated cost was the primary reason. CONCLUSION: Screening for SCT remains a relatively uncommon practice in colleges and universities, particularly in NCAA Divisions II and III, and NAIA institutions. From the institutions' perspective, the cost of testing is overwhelmingly the primary reason for not screening all athletes for SCT.

Presence of Observers Increases One Repetition Maximum in College-age Males and Females.

PURPOSE: To determine if the presence of observers affects muscular strength performance in college-age males and females. METHODS: Twenty-five women and 24 men participated in the study. Two counter-balanced trials were performed in which participants completed 1-RM tests in bench press and leg press. During one trial, two members of the opposite gender observed the 1-RM tests. During the other trial there were no observers, other than the tester. RESULTS: 1-RM for females increased 3.4±0.8 lbs on bench press (p<.001) and increased 9.2±3.8 lbs on leg press (p=.025) when observers were present. 1-RM for males increased 4.2±1.1 lbs on bench press (p=.001) and increased 18.8±5.2 lbs on leg press (p=.002) with observers present. There was no difference in the percent increase in 1-RM between males and females for either leg press (p=.71) or bench press (p=.08). CONCLUSION: College-age males and females lifted more weight during a 1-RM test when observers were present.

Physical activity and food consumption in high- and low-active inbred mouse strains.

PURPOSE: To determine the effect of innate activity level and running wheel access on food consumption in high-active (SWR/J) low-active (DBA/2J) mice. METHODS: Two strains of inbred mice were used in this study owing to their high activity level (SWR/J) and low activity level (DBA/2J). Mice were housed in individual cages, and half of the mice in each strain had free access to running wheels in their cages, whereas the other half received no running wheel. All mice consumed standard chow and water ad libitum for 13 wk during the study period. Running wheel activity (daily), food consumption (biweekly), and body mass (weekly) were recorded. RESULTS: SWR/J runners consumed more food (6.0 ± 0.4 g·d)(-1) than SWR/J nonrunners (4.7 ± 0.2 g·d(-1), P = 0.03), DBA/2J runners (4.6 ± 0.2 g·d(-1), P = 0.02), and DBA/2J nonrunners (4.2 ± 0.2 g·d(-1), P = 0.006). SWR/J nonrunners consumed more food than DBA/2J nonrunners (P = 0.03). Average daily distance and duration were significantly greater for the SWR/J runners (6.4 ± 0.7 km·d(-1) and 333.6 ± 40.5 min·d(-1), respectively) compared with those for the DBA/2J runners (1.6 ± 0.4 km·d(-1) and 91.3 ± 23.0 min·d(-1), respectively). There was a significant correlation between food consumption and distance (r = 0.74, P < 0.001), duration (r = 0.68, P < 0.001), and speed (r = 0.58, P < 0.001), respectively, in all mice. However, when considering the individuals strains, the relationship between running wheel activity and food consumption was only statistically significant for the SWR/J mice. CONCLUSIONS: Higher running wheel activity in mice was associated with increased food consumption in the SWR/J mice but not in the DBA/2J mice. In DBA/2J mice, addition of a running wheel did not result in increased food consumption, suggesting that energy expenditure of nonwheel cage activity in the control DBA/2J mice was similar to the energy expenditure of the wheel activity because body mass was similar between the two groups.

Exercise intensity during wheelchair rugby training.

The purpose of this study was to determine the ability of individuals with a cervical spinal cord injury to achieve and sustain a cardiorespiratory training intensity during wheelchair rugby. Nine wheelchair rugby players completed a continuous peak exercise test on a SciFit Pro I arm ergometer with stage increases each minute to determine peak heart rate and power output. Approximately one week after peak exercise testing, heart rate was recorded (every 5 s) during three regularly scheduled rugby training sessions. Data were analysed to determine the number of continuous minutes that participants spent above 70% of heart rate reserve under various rugby training activities. The percent of time spent at or above 70% heart rate reserve varied across participants and conditions. Continuous pushing was the least variable training condition among participants with the sample averaging greater than 73% of time above the target heart rate. Scrimmage training was highly variable across participants with a range of 0% to 98% of time above the criterion. Results of this study indicate that wheelchair rugby training enables some participants to reach a training intensity associated with improved cardiorespiratory fitness, and that the type (or kind) of training activity dictates the extent to which individuals sustain such a threshold.

Wheel access does not attenuate weight gain in mice fed high-fat or high-CHO diets.

PURPOSE: To determine the effect of a high-fat or high-carbohydrate diet and running wheel activity on body composition, body mass, and caloric intake in C57Bl/6 mice. METHODS: At 4 wk of age, five groups of C57Bl/6 mice were housed individually. Two groups had running wheels, whereas the other three groups did not. Within the running wheel groups, FAT-W consumed a high-fat diet (60.3% fat) and CHO-W consumed a high-carbohydrate diet (70.4% carbohydrate). Within the nonrunning groups, FAT consumed the high-fat diet, CHO consumed the high-carbohydrate diet, and the fifth group consumed standard chow. All groups consumed food ad libitum and were exposed to their respective conditions for 12 wk. Wheel activity, food consumption, body mass (BM), and percentage of body fat (%BF) were recorded. RESULTS: There was no significant difference in %BF or BM at the end of 12 wk between FAT-W and FAT or between CHO-W and CHO (P > 0.05). %BF was significantly higher in both FAT-W (42.9% +/- 0.6%) and FAT (45.9% +/- 0.8%) compared with CHO-W (30.8% +/- 1.4%) or CHO (33.4% +/- 1.0%; P < 0.001). BM was significantly higher in both FAT-W (42.8 +/- 0.7 g) and FAT (44.7 +/- 1.2 g) compared with either CHO-W (32.8 +/- 1.6 g) or CHO (37.1 +/- 0.8; P < 0.01). There was no difference in wheel activity between FAT-W and CHO-W (P > 0.05). Daily caloric intake was higher in both FAT-W (17.0 +/- 0.8 kcal) and FAT (15.9 +/- 0.9 kcal) compared with that in CHO-W (13.9 +/- 0.7 kcal) and CHO (13.6 +/- 0.5 kcal; P < 0.01). CONCLUSIONS: Access to a running wheel had no protective effect on BM or %BF in C57Bl/6 mice that consumed either a high-fat or a high-carbohydrate diet during a 12-wk period. Access to a running wheel did not affect caloric intake; however, average daily caloric intake was higher in mice on high-fat diets compared with that in mice on a high-carbohydrate diet.

Type of Encouragement Influences Peak Muscle Force in College-Age Women.

To investigate if the type of encouragement during a maximal voluntary isometric contraction (MVIC) had an influence on peak muscle force in strength-trained versus untrained collegiate women. Eleven strength-trained (20±1 y) and twelve untrained (21±1 y) women participated in three, five-second MVICs of seated knee extension. The three trials consisted of verbal only encouragement, verbal + visual encouragement, and verbal + pain avoidance encouragement. In all three trials, the participants received the same verbal encouragement. Trials were counterbalanced to minimize any possible order effects. A repeated measure ANOVA was used to analyze data. Any significant main effects were further analyzed using Tukey post hoc tests. There was no interaction between training status and encouragement type for all subjects F(2,42) = 1.5474, p = 0.22). For all subjects, a main effect for encouragement type was detected (F(2,42) = 6.616, p <0.05) with significant differences found in MVIC between the verbal encouragement and verbal + visual feedback (99.5±29 ft-lbs and 115.6±29 ft-lbs, p<0.01). No significant differences were found between the verbal only and the addition of pain avoidance (99.5±29 ft-lbs and 109.9±26.3 ft-lbs, p=0.069) or the visual and pain avoidance trials (115.6±29 ft-lbs and 109.9±26 ft-lbs, p=0.43). In this study, training status did not significantly influence the response to type of encouragement. Individuals produced the most force during a MVIC with verbal and visual encouragement. The incorporation of verbal encouragement and visual feedback is an important factor in eliciting peak force in college-aged women. This may have important implications in training and rehabilitation models that incorporate resistive loading of the skeletal muscles.

The effect of light color on muscular strength and power.

The purpose of this study was to assess the effect of the color of light in a room on muscular strength and power. A convenience sample of 18 men (M age = 20.4 yr., SD = 1.2) performed a modified Wingate Anaerobic Cycle Test for muscular power and a hand grip strength test in each of the following conditions: red, blue, and white (neutral) ambient light. A repeated-measures multivariate analysis of variance indicated that average muscular power was significantly higher when performing the test in the room with red light compared to rooms lit with blue light or white light. The results also indicated that grip strength was significantly higher in the room lit with white light as compared to the room lit with blue light.

Undergraduate Research: Importance, Benefits, and Challenges.

Developing and maintaining undergraduate research programs benefits students, faculty mentors, and the university. Incorporating a research component along with a sound academic foundation enables students to develop independent critical thinking skills along with oral and written communication skills. The research process impacts valuable learning objectives that have lasting influence as undergraduates prepare for professional service. Faculty members at teaching intensive institutions can enhance learning experiences for students while benefiting from a productive research agenda. The university in turn benefits from presentations and publications that serve to increase visibility in the scientific community. Whether projects are derived through student-generated or mentor-generated means, students benefit from completion of exposure to the hypothesis-driven scientific method.

Ambient-temperature beverages are consumed at a rate similar to chilled water in heat-exposed workers.

Palatability of beverages has been shown to influence drinking patterns and hydration. Cool beverages are known to enhance palatability; however, situations exist in which cooling is not possible. The purpose of this study was to determine the palatability of a variety of flavors of ambient temperature beverages. Ten healthy males performed two work trials in a temperature-controlled environment (WBGT = 30 degrees C; wet = 25 degrees C, dry = 40 degrees C, globe = 41 degrees C). In one trial, the subjects had only chilled water to drink. In the second trial the subjects drank their choice (any or all) of five ambient temperature beverages (water, fruit punch, lemon-lime, orange, and cola). Repeated measures ANOVA showed no difference in absolute or relative fluid consumption between the two trials (chilled = 1730 +/- 316 mL and 21 +/- 5 mL/kg; ambient [all five beverages combined] = 1510 +/- 219 mL and 19 +/- 4 mL/kg). There was no difference in the rate of fluid consumption between the two trials (608 +/- 88 mL/30 min and 674 +/- 82 mL/30 min, p > 0.05). Additionally, when combining all ambient-temperature, flavored beverages, consumption was significantly greater than that of ambient temperature water (1245 +/- 206 vs. 255 +/- 86 mL, p < 0.05). These findings demonstrate that providing ambient temperature beverages in a hot condition results in fluid consumption values similar to chilled water. These findings are relevant to industry in that there may be times when workers are at risk for heat-related illness due to dehydration and chilled beverages are not available. By providing flavored beverages, fluid consumption may be maintained and degree of heat-illness may be lessened.

Influence of age of exposure to a running wheel on activity in inbred mice.

PURPOSE: It is currently unknown whether the age of wheel exposure influences running wheel activity in mice. The purpose of this study was to determine whether the age at which a running wheel was introduced affected running wheel activity for a subsequent 15-wk period. METHODS: Twenty female C57Bl/6J mice (age 7 wk) were assigned to one of four experimental groups. Group 1 received a running wheel at 7 wk of age. Thereafter, groups 2, 3, and 4 received running wheels at 10, 13, and 16 wk of age, respectively. Daily running wheel activity (duration, distance, and velocity) was recorded from the time of running wheel exposure until 30 wk of age. RESULTS: A repeated-measures MANOVA found significant differences between groups for distance (P = 0.02), duration (P = 0.04), and velocity (P = 0.001) during the 15-wk concurrent running period (age 16-30 wk). Post hoc tests revealed significantly greater distance and duration in group 4 compared with group 2 and significantly greater velocity in group 4 compared with each of the other groups. Significant interactions were found between groups over time for distance (P = 0.01) and duration (P = 0.05). No significant difference between groups was observed for body weight over the 24-wk period (P > 0.05). CONCLUSION: Although differences were found between groups 2 and 4, these data suggest that the age at which physical activity is introduced has little influence on the subsequent level of physical activity in C57Bl/6J mice. However, it appears that introduction of the running wheel at 16 wk of age results in greater within group variance, suggestive of a greater environmental influence on daily running wheel activity.

Influence of Hydration and Electrolyte Supplementation on Incidence and Time to Onset of Exercise-Associated Muscle Cramps.

Context: Exercise-associated muscle cramps (EAMCs) are common among physically active individuals and are temporarily disabling; therefore, prevention is of great interest.Objective: To determine the role of hydration and electrolyte supplementation in the prevention of EAMCs.Design: Each subject completed 2 counterbalanced trials in a repeated-measures design.Setting: University of Alabama.Patients or Other Participants: College-aged men (n = 13) with a history of EAMCs.Intervention(s): In each trial, participants performed a calf-fatiguing protocol to induce EAMCs in the calf muscle group. Each trial was performed in a hot environment (dry bulb temperature of 37 degrees C, relative humidity of 60%). In the carbohydrate-electrolyte trial, subjects consumed, at a rate similar to sweat loss, a carbohydrate-electrolyte beverage with sodium chloride added. In the hypohydration trial, subjects were not allowed to consume any fluids.Main Outcome Measure(s): We measured the incidence and time to onset of EAMCs.Results: Nine participants experienced cramps in the carbohydrate-electrolyte trial, compared with 7 in the hypohydration trial. Of the 7 individuals who had EAMCs in both trials, exercise duration before onset was more than doubled in the carbohydrate-electrolyte trial (36.8 +/- 17.3 minutes) compared with the hypohydration trial (14.6 +/- 5.0 minutes, P < .01).Conclusions: Consumption of a carbohydrate-electrolyte beverage before and during exercise in a hot environment may delay the onset of EAMCs, thereby allowing participants to exercise longer. However, it appears that dehydration and electrolyte loss are not the sole causes of EAMCs, because 69% of the subjects experienced EAMCs when they were hydrated and supplemented with electrolytes.

The impact of resistance training on distance running performance.

Traditionally, distance running performance was thought to be determined by several characteristics, including maximum oxygen consumption (VO(2max)), lactate threshold (LT), and running economy. Improvements in these areas are primarily achieved through endurance training. Recently, however, it has been shown that anaerobic factors may also play an important role in distance running performance. As a result, some researchers have theorised that resistance training may benefit distance runners. Because resistance training is unlikely to elicit an aerobic stimulus of greater than 50% of VO(2max), it is unlikely that resistance training would improve VO(2max) in trained distance runners. However, it appears that VO(2max) is not compromised when resistance training is added to an endurance programme. Similarly, LT is likely not improved as a result of resistance training in trained endurance runners; however, improvements in LT have been observed in untrained individuals as a result of resistance training. Trained distance runners have shown improvements of up to 8% in running economy following a period of resistance training. Even a small improvement in running economy could have a large impact on distance running performance, particularly in longer events, such as marathons or ultra-marathons. The improvement in running economy has been theorised to be a result of improvements in neuromuscular characteristics, including motor unit recruitment and reduced ground contact time. Although largely theoretical at this point, if resistance training is to improve distance running performance, it will likely have the largest impact on anaerobic capacity and/or neuromuscular characteristics. The primary purpose of this review is to consider the impact of resistance training on the factors that are known to impact distance running performance. A second purpose is to consider different modes of resistance exercise to determine if an optimal protocol exists.